A well known and common product used to connect electrical wires is a twist-on or screw-on wire connector. These connectors are used to connect the stripped ends of two or more insulated or non-insulated conductors. Typically these twist-on wire connectors include a plastic insulating shell and a wire spring supported therein. The wire spring may be conical in shape so that when the connector is placed over the stripped ends of insulated electrical conductors and twisted thereon, the conductors are brought into electrical engagement with each other within the spring. In order to accommodate the stripped ends of the electrical conductors in the conical wire spring, the spring is constructed to resiliently radially expand. Such expansion permits two or more conductors to be supported within the conical spring.
Further, the resiliency of the spring securely holds the conductors together in the conical spring establishing electrical connection therebetween. As may be appreciated, mechanical securement of the conductors in the connector as well as the electrical connection therebetween is maintained by the radially inward compressive forces exerted by the expanded spring on the terminated conductors. Overexpansion of the spring during termination could cause the loosening of the connector over time, possibly resulting in an open connection between the conductors.
Attempts have been made to control the outward radial expansion of the conical wire spring during termination. One technique is to use the construction of the shell itself to exert a force against the expanding spring to control the rate of expansion of the spring. The prior art has seen numerous shell designs as well as materials to form the shell which attempt to provide such expansion control. U.S. Pat. No. 4,227,040 issued to Scott shows one example of shell modifications which attempt to control the rate of spring expansion. The connector shown in the '040 patent employs a plurality of longitudinally extending ribs spaced about the internal periphery of the shell. The ribs lie in engagement with the outer surface of the conical spring along the length thereof and retard the rate of expansion of the spring. However, it has been found that the particular shape and disposition of the ribs in the '040 patent provide such a degree of resistance to spring expansion that the connector may be difficult to readily twist onto electrical conductors especially in a repetitive installation setting.
In that regard, improvements have also been seen in wire connectors where the outside configuration of the shell is modified to render it easier to twist onto the conductors. One well known technique is to use diametrically opposed outwardly directed wings which fit between the thumb and forefinger of the installer to provide a degree of leverage to permit the twisting of the connector onto the connectors. The above-described '040 patent shows one example of the type of wings known in the prior art. It has been found that while the wings provide additional leverage useful in facilitating twisting of the connector on to the insulated wires, the particular shapes of wings known in the prior art are not ergonometrically comfortable for use by the installer. In situations where the installer has to make numerous such terminations in a short period of time, significant discomfort may be encountered by the installer. It is therefore desirable to provide an improved configuration for the shell which permits the installer to more comfortably terminate conductors with a twist-on wire connector.